FIGURE 2.

Significance of fatty acid and isopropyl for lipophenol toxicity and protection of ARPE‐19 against atRAL. A, selective protection by IP fatty acid conjugates (IP‐FA). ARPE‐19 cells were cultured in 96‐well plates and incubated with lipophenols (10‐40 μmol/L) for 1 h, and atRAL (25 μmol/L) was added for 4 h co‐incubation. Culture medium was changed, and cell viability was determined 16‐20 h later by MTT assay. Bars indicate SD of the mean (n ≥ 5). Cytotoxicity effects of free fatty acid (B) and of IP‐FA (C). ARPE‐19 cells were incubated with different concentrations for 24 h, and cell viability was determined by MTT assay. PUFA concentrations were selected according to Liu et al48 Bars indicate SD of the mean (n = 4‐10). D, E, Significance of phloroglucinol (P) and isopropyl radical (I). Polyunsaturated fatty acid (PUFA) and P‐PUFA conjugates (40 μmol/L) were compared for their cytotoxicity on ARPE‐19 cells for 24 h (D). P‐PUFA (40 μmol/L) was also compared to IP‐PUFA (40 μmol/L) for their efficacies to protect ARPE‐19 from atRAL‐induced cell death (E). Cell viability was determined by MTT assay. Bars indicate SD of the means (n = 3). All data are expressed as a percentage of untreated cells. P, phloroglucinol; IP, isopropyl‐phloroglucinol; LA, linoleic acid (C18:2 ω6); ALA, linolenic acid (C18:3 ω3); EPA, eicosapentaenoic acid (C20:5 ω3); DHA, docosahexaenoic acid (C22:6 ω3); and C22 (saturated)